1. Field of the Invention
The present invention relates to a communication control method preferably applied when various information is transmitted by means of a wireless signal, for example, to construct a local area network (LAN) among a plurality of devices, and a transmission apparatus using this control method.
2. Description of the Related Art
Conventionally, in a relatively small range such as home or office, when a local area network is constructed among a plurality of apparatuses such as various video apparatuses, personal computer machine, or its periphery so as to transmit data handled by these apparatuses, a wireless signal transmitter/receiver (a wireless transmission apparatus) is connected to each apparatus so as to enable data transmission through wireless transmission, instead of direct connection among apparatuses via a signal line.
A local area network is constructed through wireless transmission, thereby making it possible to simplify a system configuration without requiring direct connection among apparatuses via a signal line or the like.
In the meantime, in the case where a local area network is constructed by using a plurality of wireless transmission apparatuses, if signals are transmitted simultaneously from a plurality of transmission apparatuses using a same transmission bandwidth, a transmission error may occur. Thus, communication among transmission apparatuses in the network is required to access-control by means of any method.
As a conventionally known access control method, for example, in a small scale wireless network, there is exemplified a method for integrally managing communication among transmission apparatuses (nodes) in the network by means of a transmission apparatus (a route node) serving as a central part using start-type connection. Specifically, processing for controlling data transmission from other transmission apparatuses is achieved by means of polling control from the transmission apparatus of a central part, for example.
However, to perform transmission processing using such star-type connection, it is presumed that a transmission apparatus serving as a central control station performing processing for transmission control is capable of performing wireless communication directly with all other transmission apparatuses in a network system. Therefore, there has been a problem that a wireless communication network construction range is limited within the range capable of directly making communication with the central control station; and the thus constructed network is available in a limited range, which depends on a transmission output of an electric wave of the central control station.
In addition, during transmission control processing using star-type connection, with respect to transmission control or network management also, in the case where direct communication with the central control station is disabled, it has been necessary to disconnect an invalid transmission apparatus from the network. Therefore, there has been a problem that, in the case where a mobile station movable in the network is admitted as a transmission apparatus, control by the central control station becomes very complicated. That is, for the central control station to grasp a position of the mobile station, it has been necessary to transmit and receive a signal for connection check at a short period, and frequently supervise a connection state among the central control station and the mobile station.
To solve these problems, for example, it is considered to construct a distributed network configuration in which communication is made only among stations capable of performing direct communication instead of predetermination of the central control station. In this distributed network, if a remote station is distant, it is required to transmit data by relaying a number of stations. Every time such relaying is performed, it is required to perform processing for transmission start with a remote station for communication. As a result, there has been a problem that data transmission is delayed every time the number of steps performing relaying is increased. There has been another problem that a good transmission state cannot be obtained unlike a case in which integrated communication management from a central control station is performed as in polling control.
It is an object of the present invention to well control a station incapable of directly making communication with a control station in the case where an attempt is made to control communication in a network system by means of the control station.
In a communication control method according to the present invention, when an access of wireless communication among a plurality of communication stations is polling-controlled by a control station, polling control information is transmitted to a specific communication station incapable of directly making wireless communication with the control station by relaying a predetermined communication station.
According to this communication control method, polling control information can be transmitted to a communication station incapable of directly making communication with a control station.
A transmission apparatus according to the present invention comprising:
receiving means for receiving polling control information to be transmitted from a control apparatus;
storing means for temporarily storing the received polling control information by the receiving means; and
transmitting means for relay-transmitting the stored polling control information by the storing means to a specific transmission apparatus.
According to this transmission apparatus, the received polling control information by the receiving means can be relay-transmitted from the transmitting means to another transmitting apparatus.